The way to get this is to avoid the Compromise of 1790. This solves the big political problem raised by
@SeaBos, since if no compromise had been raised, the capital probably
would have ended up in New York. This is what I assume the fourth point mentioned by the OP refers to. However, the compromise wasn't about the slave trade. It was about the assumption of state debts by the federal government.
The background was: various states, primarily in the South and most famously Virginia, had paid off all or most of their war-time debts. Other states, primarily in the North, had not paid off their debts. Surprise, surprise: the North wanted the Federal government to assume all states' debts. This would mean that all states would have to contribute to paying off the increased Federal debt. which meant that the South, after paying their own debts, would have to pay
again to help pay off the outstanding Northern debts. Southerners unsurprisingly objected to this. At the same time, the South felt that the Federal capital should be in the South, while the North felt it should be... well, in the North. They reached a compromise, whereby the North would agree to a Federal capital in the South, if the South would agree to Federal assumption of all states' debts.
So no Compromise of 1790 means that the capital remains a contended issues, which probably means it ends up further North than in OTL. NYC is a likely option. Meanwhile, the Northern states have to sort out their own debt issues, and the precedent of all states having their own debts and also
paying off their own debts is set. Ultimately, that may be far more favourable to Southern interests than having the capital...